Cutting instruments and methods of making same

ABSTRACT

The specific disclosure is directed to razor blades and methods of making the same wherein the cutting edge formed by two intersecting surfaces is sputter deposited with a refractory material which is subsequently overlaid with a sputter deposited coating of material displaying adhesion to a final lubricious coating.

United States Patent 1191 Lane et al.

[ 1 Oct. 14, 1975 1 CUTTING INSTRUIVIENTS AND METHODS OF MAKING SAME[75] Inventors: George C. Lane, Danbury; Phyllis M. Curtis, Simsbury;Arthur E. Michael, Middletown, all of Conn.

[73] Assignee: Warner-Lambert Company, Morris Plains, NJ.

[22] Filed: Apr. 18, 1973 [21] Appl. No.: 352,374

Related US. Application Data [63] Continuation of Ser. No. 144,509, May18, 1971.

Charschan et a1. 204/298 3,402,468 9/ 1968 Kiss et a1. 30/346.533,419,414 12/1968 Marks 117/70 3,480,483 11/1969 Wilkinson..... 117/71 X3,518,110 6/1970 Fischben 117/93.4 3,632,494 1/1972 Herte et al.....204/192 3,774,703 11/1973 Sanderson 117/75 FOREIGN PATENTS ORAPPLICATIONS 1,193,067 5/1970 United Kingdom 76/ 104 PrimaryExaminerLeonidas Vlachos Attorney, Agent, or Firm-Albert H. Graddis;Frank S. Chow [57] ABSTRACT The specific disclosure is directed to razorblades and methods of making the same wherein the cutting edge formed bytwo intersecting surfaces is sputter deposited with a refractorymaterial which is subsequently overlaid with a sputter deposited coatingof material [56] References Cited displaying adhesion to a finallubricious coating.

UNITED STATES PATENTS 2,408,790 10/1946 Mack 76/104 66 Claims, 9 DrawingFigures 3 L 1 2 l l f fflzzzfnmv (EN/N i M mini/rm DEM-SHIV?OffOS/l'lfl/V US. Patent Oct. 14, 1975 Sheet 2 of4 3,911,579

US. Patent Oct.14,1975 Sheet30f4 3,911,579

U.S. Patent Oct. 14, 1975 Sheet 4 of4 3,911,579

CUTTING INSTRUMENTS AND METHODS OF MAKING SAME CROSS-REFERENCE TO ARELATED APPLICATION This application is a continuation of U.S. Pat.application Ser. No. 144,509, filed May 18, 1971.

BACKGROUND OF THE INVENTION The present invention generally relates to amethod for making razor blades and is more particularly directed to amethod for producing a razor blade having a cutting edge displayingcertain advantages characteristics associated with refractory materials.

The razor blade industry has long sought to produce a product having anextremely sharp cutting-edge possessing both long life and concomitantlycorrosion resistance. The achievement of these desires has beenassociated with the producing of a blade made in some fashion from arefractory material. Particular attention has been directed to sapphireor, more broadly speaking, corundum.

Refractory materials by definition comprise various compoundscharacteristically having a high relative hardness, resistance toworking and abrasion under conditions of high temperature, and inertnessunder most atmospheres and conditions. the making of a razor blade frommaterials such as these has obvious difficulties. If the refractorymaterial is inherently resistant to working and abrasion, it must,therefore, be extremely difficult to perform the grinding and honingoperations necessary to the production of a modern razor blade. It isfurther characteristic of these materials that they are resistant tobending and thusly do not conform to the strip methods of making bladeswhich are universally in practice today and lead to the economicproduction of the final product.

Razor blades made from refractory materials, for instance, ceramics,have been extremely difficult to manufacture and, therefore,economically unfeasible under the conditions of todays market. U.S. Pat.No. 3,543,402, R. M. Seager, issued Dec. 1, 1970, entitled CeramicCutting Blade, discloses a method, and the resultant product, for makinga razor blade of refractory material. The difficulties involved and thestringent requirements which must be followed are detailed in thespecification of this patent and point to its unfeasibility, aspreviously mentioned. It must be further noted that refractory materialsgenerally do not display the toughness associated with metals,particularly those used in cutting instruments, and their use in view ofthis is questionable. The orientation of the ceramic crystals and theirsize become extremely significant when it is realized that the radius ofthe final apex of most razor blades manufactured today is in theneighborhood of 300 to 500 Angstroms. The abrading or loss of evensingle crystals from an edge thusly constructed may be of significanceto its cutting and life properties.

One of the most significant advances in the art of razor blades has beenthe use of lubricious coatings applied to the cutting edge. This methodof achieving a reduction in the cutting forces involved (shavingcomfort) has evolved over a lengthy span of time commencing as far backas the 1930s, and even earlier if one considers the use of shavinglathers in this regard, ultimately resulting in the application oflubricious polymer coatings to the razor blade edges. It may be safelysaid that most razor blades produced today contain a coating ofpolytetrafluoroethylene (PTFE), which substance has provided anextremely low coefficient of friction and an adherence to the cuttingedge commensurate with the ultimate life of the edge itself, i.e., thePTFE appears to remain in operable condition for as long as the bladeedge maintains a cutting edge sufficient to sever normal beard hairs.This latter point has been empirically tested and verified through thestatistical analysis of data received from extremely large shavingsamples.

U.S. Pat. No. 3,518,110, issued June 30, I970, lnventor: Irwin W.Fischbein, entitled Razor Blade and Method of Making Same", discloses amethod for applying PTFE and like low friction polymeric materials torazor blade edges. This patent does not state the mechanism of PTFEadhesion to the blade but simply hypothesizes that a monolayer of thelubricious material in some fas ion, either mechanically or throughintermolecular bonding, produces interfacial bonding forces greater thanthe cohesive forces internal to the coating thereby permitting aminimization of friction and further providing an elimination ofasperities between the cutting surface and the material to be severed.Efforts have been made to determine a more exact hypothesis for theapparent improvement in shaving comfort, but, to date, not firm andprovable conclusions have been reached. It must be emphasized, however,that the adhesion of the lubricious coating appears to be sufficient tomaintain a low coefficient of friction throughout the useful wear lifeof the blade edge, i.e., blade usefulness is limited by edge breakdownas opposed to loss of lubricity. Experience in the use of razor bladematerials other than chromium stainless steel as used in the Fischbeinpatent has indicated wide variance in the adhesion properties of thelubricious coating; stainless steel and pure chromium and oxides thereofprovide extremely long life or adhesion of the coating. Other materials,for instance, platinum and, generally, refractory materials, show adecreased and in some instances no adhesion.

The prior art, although replete with the application of differentmaterials to razor blades, all claimed to improve blade quality andperformance in some manner, has generally failed to provide a bladereflecting the overall shaving performance and comfort found in themodern razor blade in combination with the durability of refractorymaterials as previously discussed. The Seager patent, in addition to thesignificant problems previously indicated, totally fails to disclose theperformance of the claimed blade relative to modern-day products and, infact, does not show how a final product might be achieved. It is,therefore, an object of this invention to provide a razor bladeexhibiting improved qualities.

It is another object of this invention to provide an improved razorblade of a refractory material.

Another object of this invention is to provide 2 method for applying arefractory material to a ram: blade.

Another object of this invention is to provide 2 method for applying alubricious material to a razol blade of refractory material.

Yet another object of this invention is to provide 2 method fordepositing a refractory material on a sub strate.

Still another object of this invention is to provide a method fordepositing corundum onto a substrate.

Still another object of this invention is to provide a method forsputter depositing coatings of material onto a razor blade.

It is yet another object of this invention to provide a method formaking razor blades of refractory material in a continuous batchprocess.

SUMMARY OF INVENTION In accordance with this invention, a method formaking a razor blade is presented. The blade is formed from a suitablematerial and has an edge portion which consists of two intersectingsurfaces which may be honed or made by some other forming process. Atleast the surfaces comprising the edge as well as the ultimate apex atthe intersection are sputter deposited with a refractory material andthen, in order to provide adhesion of a final coating of lubriciousmaterial, the edge is coated with a second material having the desiredadhesive characteristics.

The invention further provides a method of applying an adherent coatingof lubricious material to a razor blade edge formed by the intersectionof two surfaces of refractory material. This method involves the coatingof the refractory surfaces with an overlay of material displayingadhesion to both the surfaces and the lubricious material.

Also in accordance with the invention, there is disclosed a method inwhich razor blades having edges formed by two intersecting surfaces aresputter etched in a first vacuum chamber. The blades are then movedthrough a vacuum interlock to a second chamber in which they are sputterdeposited with a refractory material. After deposition of the refractorymaterial, the blades are then moved through a second vacuum interlock toa third chamber wherein the coating of material displaying adhesion to asubsequent lubricious coating is sputter deposited on the refractorymaterial. Subsequent to the above steps, the blades are moved through athird vacuum interlock to a fourth vacuum chamber from which they areeventually vented to the atmosphere prior to a final coating with thelubricious material.

Yet another aspect of this invention involves a cutting instrumenthaving an elongate edge of narrow included angle formed by twointersecting surfaces of a refractory material onto which an overlaycoating is placed, the overlay coating having adhesion to the finalcoating of a lubricious material.

The invention is also directed to a method for depositing corundum ontoa substrate. This method involves disposing the substrate in anevacuated chamber having an electrode on which is mounted a target ofcorundum. An ionizable gas is introduced into the chamber and a plasmais estabished by imposing an RF potential between the electrode and thesubstrate. Particles dislodged from the target by impingement of gasions formed in the plasma by the collision of RF excited electrons andthe ionized gas are then deposited on the substrate with the neededlevel of energy to form the desired crystal structure and orientation.

The foregoing summary of the invention as well as other objects andadvantages will be made apparent upon a study of the following drawingsand the detailed description of preferred and exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a functional block diagramof the method and apparatus for producing a razor blade having an edgeformed of refractory material.

FIG. 2 is a partially cross-sectional functional schematic showing atypical sputtering chamber.

FIG. 3 is a partially cross-sectional functional schematic showing amulti-chambered continuous batch sputtering system.

FIG. 4 is an outline drawing of a typical single-edge razor blade.

FIG. 5 is a diagrammatic cross-sectional drawing of a typicalsingle-edge razor blade showing in distorted fashion material coatings.

FIG. 6 is a cross-sectional drawing of a batch of razor blades mountedin a holder.

FIG. 7 is a plan view of a fixture for holding a continuous coil ofrazor blade.

FIG. 8 is a cross-sectional view of FIG. 7.

FIG. 9 is a plan view ofa fixture for holding a plurality of razor bladecoils.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detaileddescription is made in coordination with the drawings of thisapplication and discloses the functional and structural features of theinvention. Throughout the drawings and description, conventionalsymbology and nomenclature is used, and similar units appearing in thedifferent drawings are designated by the same number. It is intendedthat the descriptions set forth herein be exemplary of the invention andnot delimiting of its scope.

A general outline of the steps involved in the manufacturing process forproducts conforming to the novel features of this application are shownin FIG. 1. As obvious from the nomenclature of the drawing, this processoutline is specifically involved with the fabrication of an improvedrazor blade. The blade is first manufactured in accordance with normalprocedures well known in the art. The stainless steel or otherapplicable blade material is formed into strips of convenient dimensionand then passed through punching, heat treating, printing, grinding, andfinally honing to produce a final cutting edge formed by theintersection of two surfaces. As previously indicated, this bladefabrication step 1 is amply detailed in the prior art and well known tothose skilled in the art. It would serve no useful pupose to go moredeeply into the cutting edge manufacture other than to indicate that thedifferent steps involved may be altered to achieve desiredcharacteristics on the edge. To some degree, these achievablecharacteristics may affect the ultimate process but do not form anyintrinsic contribution to the novel concept of the applicants.

After the final edge of the razor blade is formed, which edge is grosslydepicted in FIG. 5 of this application and is shown having an includedangle A which normally varies between 15 and 25 but may, depending uponthe basic substrate orblade material, vary in a much wider degree, it isthen passed on to a cleaning step 2. The cleaning step is utilized toremove the contaminants formed on the edge during the fabrication step.Normally these contaminants comprise cutting oils, greases, printinginks, etc., which are a necessary part of the prior process. Again, theprior art quite adequately documents the type of cleaning needed and theinstruments employed to effect its attainment. In a process used by theapplicants, the blade edges, while stacked in juxtaposition arrangement,are subjected to jets of trichloroethylene, which fluid is constantlycleaned through a filtration process. Employment of other devices suchas ultrasonic energy, agitation, air, etc., are recognized, but, onceagain, the process used does not lend any novel contribution to theapplicants invention.

The steps depicted in that portion of the process 3 are intimatelyinvolved with the applicants novel process. Contained in this portion ofthis process are the steps of surface preparation 10, Deposition I, 11,Deposition II, 12, and Deposition III, 13, which are performedsequentially after the cleaning 2. The surface preparation atomicallycleans the cutting edge of the blade and prepares it for properacceptance of subsequent depositions; it normally involves the sputteretching or glow discharge cleaning of the edge, but may be achieved byany process which adequately cleans the intersecting surfaces formingthe edge by the atomic removal of blade substrate material, contaminantsand adsorbed gases. The description of the invention hereinafterpresented in the body of this application will describe those surfacepreparations believed most adaptable to the inventive method of theapplicants, but it must be recognized that this preparation may varywithout departing from the scope of the applicants novel contribution.Deposition 1 coats the blade edge formed by the intersecting surfaceswith a refractory material by a suitable deposition process. In thatrefractory materials are generally of a dielectric nature and sincefurther radio frequency sputtering has achieved desirable performanceresults, this first coating of refractory material is applied by an RFsputtering process. Again, however, it must be recognized that anysputtering process, whether it be alternating current of sufficientlyhigh frequency or a modified direct current sputter process having meansfor dissipating the charge sheath formed about the cathode or variantforms of bias sputtering, may be utilized. The nature and apparatus ofsputtering is adequately set forth in Chapter 3, pp. 3-2 through 3-35,in Handbook of Thin Film Technology" edited by Leon l. Maissel andReinhard Glang, published by McGraw-Hill Book Company, 1970. It issignificant to point out at this juncture that the nature of thedeposition process is not necessarily significant to the invention aslong as it achieves a satisfactorily adherent and continuous coating ofthe refractory material which at this time can, within the applicantsknowledge, only be achieved by a sputtering or equivalent process.

The refractory material to which greatest attention is currently beingdirected in the application of this invention is synthetic sapphire or,as previously indicated, corundum; This material when sputtered on theedge of a razor blade clearly displays the characteristics previouslyset forth herein which are desirable and necessary to the production ofan improved razor blade. lt

'mustbe noted, however, that other generally classified Qrefractorymaterials such as glass, quartz, alumina, beryllia, silicon carbide,tungsten carbide and boron nitride amongst others may be successfullyused in razor blade or cutting edge applications. It must be furtherrecognized that this invention is not necessarily limited to refractorymaterials but may find equal application to any material displayingdesirable blade or cutting edge characteristics without having thenecessary or preferred degree of adhesion to a subsequent lubriciouscoating. Further, it is significant to point out that in sputterdepositing a preferred crystalline structure of aluminum oxide, analuminum target may be used with a reactive oxygen containingatmosphere. With appropriate choice of operating parameters and oxygen,a desired morphology and composition may be deposited.

Deposition ll constitutes the coating of the blade edge with thematerial displaying the desirable adhesion to the subsequent coating oflubricious material. Rather immense statistical evidence has indicated asuperior degree of performance by the use of preferably chromium or somechromium alloy coatings. This material not only adheres strongly to thelubricious coating but provides a hard and durable shaving edge. Inaddition to chromium, other materials, namely, platinum, aluminum,titanium and iron, amongst others, and alloys of these metals, havefound application to razor blade edge coatings. As our knowledge of themechanics of adhesion increases, it may very well develop that othermaterials we well as the one mentioned herein may find applicationwithin the scope of this invention. The preferred method of depositioninvolves the radio frequency sputter depositing of chromium onto theblade edge. Of course, DC sputter coating may be used to apply thesecond material to the razor blade, but it has been determined that inoverall aspect the use of RF sputtering techniques seems to lend adecided improvement to the product. It is generally hypothesized thatthis improvement is to some degree due to the inherent cleaning anddesorption of gases on the surface of the razor blade edge which takesplace during the RF sputtering process. The second material must bedeposited to a thickness sufficient to provide the desired degree ofadhesion to the subsequent lubricious material. It has been found thatthis desired characteristic is achieved by applying a coating ofapproximately 25 Angstrom units in thickness. The performance of such athin coating is extremely surprising in that it forms only approximatelya coating of five atomic layers in thickness and further cannot beconsidered continuous over the entire surface of the refractorymaterial. It is pointed out, however, that this material may bedeposited to any thickness sufficient to provide the desired adhesionlimited only by the requirement that the thickness not in any waydetract from the sharpness of the cutting edge. It has been found thatthicknesses of up to and greater than ap- 1 proximately 300 Angstromsare completely compatible with the cutting properties of the blade edge.

It is not understood why such an extremely thin coating of materialproduces such remarkable improvements in adhesion of the lubriciouscoating. It is hypothesized that the second material provides adesirable crystal or other surface morphology to which thepolytetrafluoroethylene or other lubricious material may find favorableadhesion through mechanical locking of the surfaces. Although suchhypothesis seems totally acceptable for thicker films, it can bereasonably questioned when considered withfilms as thin as 25 Angstroms.In this regard, it has been theorized that perhaps the thin cromium orother material coating alters the surface energies of the material insuch a manner as to permit some form of energenic linking between themolecules or atoms of the polymeric coating and the overlay coating ofchromium either alone or in combinationwith the first coating ofrefractory material. The applicants, however, do not wish to be limitedto the mechanism of adhesion achieved in the practice of this invention,but rather simply use the ultimate fact of its performance within thecontext of their novel contribution.

Deposition III involves the final process step for coating the razorblade edge with a lubricious material. As previously set forth, thiscoating of lubricious material is generally considered as necessary forthe proper performance of all razor blades manufactured today. TheFischbein patent, supra, adequately adequately describes methods forapplying a coating of polytetrafluoroethylene, which method is whollycompatible with the novel process of the applicants. Briefly, after theDeposition II coating is applied, the blades are in stacked alignmentsprayed with an aqueous or Freon based dispersion of low molecularweight polytetrafluoroethylene, the thickness of such coating beingsubstantially greater than 2,000 Angstroms. After spraying, the bladesare then subjected to a heat somewhere in the range in excess of 600 F.for a limited period of time. During this heating process, the bladesare maintained in a substantially inert environment comprising nitrogenor cracked ammonia. It is, however, pointed out that certain morereactive gases may be added to the environment or ambient conditions ofthe blade during heating to provide certain desired characteristics suchas improved adhesion of the polytetrafluoroethylene. The improvements inadhesion lent by the variations in the heating atmospheres, however, arenot considered as part of the applicants invention and are generallyconsidered negligible with respect to the improvement in adhesionprovided by Deposition II. In addition to polytetrafluoroethylene, otherpolymeric materials have found some application to razor blade edges,although up to this time not providing the same degree of performance aspolytetrafluoroethylene. These are polypropylene,polyhexafluoropropylene, polychlorotrifluoroethylene and polyethylene,amongst others. It is entirely conceivable that the polymers mentioned,as well as others not presently considered for use, may find futureapplication to razor blade edges if the necessary modifications to theprocess to achieve desirable performance are discovered or if thepolymer molecules are in some manner modified or cross-linked to altertheir characteristics in an advantageous manner.

FIG. 2 presents in schematic outline form a partial cross-section of avacuum chamber 58 associated with ancillary equipment without thechamber 58 and internal appendages within the chamber 58 necessary tothe performance of the applicants method. Within the chamber there isdiagrammatically presented an RF electrode 56 surrounded by a shield 56necessary to prevent leakage of RF to its surrounding environment. Onthe face ofthe electrode there is located a target 57 which, dependingupon the step of the process being performed, may comprise therefractory material, Deposition I; or the Deposition II'material,namely, chromium, or other material as previously mentioned. The target57 may be cemented to the face of the electrode or preferably mounted tothe electrode through screws or other fastening devices which do notextend to the front of the target thereby preventing any contaminationof the target or the substrate to be sputtered by the material of whichthe fastening devices are made. The electrode 56 is brought by means ofsuitable RF insulators and couplers to the outside of the chamber forits connection to the source of energy. The second electrode 20comprises a member which includes the blade or blades or other deviceson which material from the target 57 is to be sputter deposited. An RFlead is brought from the substrate through the wall of the chamber bymeans of suitable RF connectors and couplers to the outside source ofenergy. Similarly to the electrode 56, an RF shield 20' is provided toprevent leakage of energy to the surrounding environment.

Movement of the shutter 53 is provided by a mechanical linkage 54brought through the walls of the vacuum chamber 58 to a control unit 55.This mechanical drive train 54 which may comprise any suitablemechanical linkage, for example, driven gear systems or flexible shaftsor rack and pinion or screw rod drives, is provided with the necessarydriving force by the control unit 55 which may comprise any suitable ACor DC motor drive limited by microswitches within the chamber sensingthe position of the shutter 53. Of course, the passage of the mechanicallinkages through the vacuum chamber 58 must be adequately sealed by ORing configurations, bellows or other suitable sealing members.

A coolant unit 26 normally comprises a pump or pressure line for forcingwater or other suitable coolant through passages provided within theelectrode 56. In the sputtering process significant heat is generated inthe electrode 56 and generally it is found advantageous, if not alwaysnecessary, to provide some medium for heat transfer from the electrode56 in combination with the target 57 in order to prevent burnout of thesputter electrode configuration. Of course, any other members which mayduring any particular process require coolant may be provided with suchmedium by the same coolant unit 26. During the sputtering process, it isnecessary to generate an electrical plasma. This plasma is maintained bythe presence of an ionizable gas. In the present invention, Argon isfound most suitable and is provided to the chamber by the Argon unit 25.Suitable valving for admitting the desired amount of Argon is well knownto those skilled in the art and may provide a needle valve arrangementof rather simple construction. The nitrogen vent unit 39, similar to theArgon unit 25, provides for the admission of a gas to the inside of thevacuum chamber 58. The nitrogen vent 39 serves two purposes to theapparatus shown in FIG. 2. Firstly, it permits purging of the internalspace of the chamber 58 prior to commencement of the steps of theprocess, thereby providing a drying and cleaning action to the chamber58. Secondly, the nitrogen vent unit 39 provides through a suitableneedle valve or other arrangement for the admission of gas to thechamber 58 prior to the opening of the chamber upon completion of aprocess step, thereby preventing potential damage to the equipment aswell as the seals, etc., associated with the equipment which may beattendant to the sudden loss of vacuum. Further, it may be extremelydifficult to open various parts of the chamber 58 without a reduction invacuum provided by the nitrogen vent 39. It is pointed out that thecoolant unit 26, the Argon unit 25, and nitrogen vent unit 39 must allbe adequately sealed to prevent leakage within the chamber 58environment.

A DC meter unit 48 provides a means for measuring the bias voltage whichis built up on the electrode 56 during sputtering operations. This biasvoltage is normally considered a figure of merit with respect to thedegree of sputtering or sputtering rate which is preferred during thecoating process. The RF generator 31 provides the energy source for theradio frequency sputtering operation. Generally, in conformance with FCCRegulations, a frequency of 13.56 megacycles is used. It must be pointedout and recognized, however, that any suitable high frequency may beemployed notwithstanding FCC Regulations. The matching Z unit ormatching impedance unit 33 provides for proper power matching orimpedance matching of the RF generator 31 and the input to the RFelectrode 56. This impedance viewed looking into the electrode 56-is acomplex affair determined not only by the configuration of theelectrodes internal to the chamber 58 but by the operation of the plasmagenerated during the sputtering cycle. This matching unit 33 comprisesnormally various inductive and capacitive components in pi, T and seriesor parallel arrangements necessary to achieving certain impedancematching. A copending patent application of one of the applicants, viz.,U.S. Ser. No. 680,926, filed Nov. 6, 1967, now U.S. Pat. No. 3,632,494,dated Jan. 4, 1972, shows one matching unit 33 configuration which maybe employed with the device shown in FIG. 2 or with similarly arrangedsputtering equipment. It must be realized, however, that theestablishing of the matching unit 33 parameters is substantially anempirical process varying to some degree with the particular sputteringequipment being utilized. It is considered that the design anddetermination of the matching unit 33 configuration is well within thatlevel of knowledge commensurate to those individuals ordinarily skilledin the art.

The switch S provides for altering the connections from the electrodesto the ground of the system and to the matching unit 33 for achievingthe different steps of the sputtering process. This switch S maynecessarily be ganged with other switches or switch in the matching unit33 to alter the output impedance configuration to conform with thechanged impedance level when the switch S is moved to its secondposition. In position 1, it is obvious that the RF energy is applied tothe substrate electrode 20. In this circuit configuration, a plasma isformed which generates a sputtering action by attracting positive Argonions toward the substrate electrode 20. This attraction is mainlyprovided by the buildup of a negative bias voltage on the electrode 20which results essentially from a series capacitor in the line betweenthe substrate electrode 20 and the matching unit 33. This capacitor'isnormally provided within the matching unit 33. This configuration thussatisfies the requirements of the surface preparation step 10 byatomically cleaning the edge of the blades or other cutting instruments.Naturally, the rate of material removal must be carefully and closelymaintained.

When switch S is placed in position 2, the substrate electrode isbrought to system ground as is the chamber 58 while the RF energy isconnected through the matching unit 33 to the electrode 56. When in thisconfiguration, two desirable results may be achieved. With the shutterS3 interposed between the substrate electrode 20 and the RF electrode56, the buildup of the plasma within the chamber 58 causes sputtering ofmaterial from the target 57. This material, however,

cannot impinge upon the substrate 20 due to the interposition of theshutter 53 thereby cleaning the target surface 57 prior to thedeposition of any material onto the substrate electrode 20. Once theshutter 53 is removed by the coaction of control unit 55 drive linkage54, continued application of RF energy brings about the sputterdeposition of target material onto the substrate surface or, in thiscase, the cutting edges of the razor blades. As is obvious from themechanical configuration of the sputtering apparatus, the chamber mustbe opened between steps of Deposition I and Deposition 11. Theshortcomings presented by this necessitated opening and re-evacuating ofthe chamber 58 are overcome by equipment conforming essentially to thatpresented in FIG. 3 of this application. There is shown in FIG. 3 acontinuous batch sputtering process apparatus which is uniquelyadaptable to the applicants invention. Prior, however, to discussing theoperation of this apparatus within the context of the applicantsprocess, operation of the equipment as well as the steps of theapplicants novel process will be considered with respect to theequipment of FIG. 2.

In considering an operational analysis of the equipment and the processinvolved, it may first be beneficial to consider the blade holderconfiguration presented in FIG. 6. FIG. 6 shows in distorted dimension apartial cross-sectioning of a typical blade stack held transversely bythe blade holder. It has been found for reasons not wholly understoodthat in order to achieve the desired uniformity of sputter depositioncoating both across the individual blades as well as throughout theentire stack of blades 101 the geometric configuration of the holderends 102 is extremely important. The apex of the end portions 102 mustlie in substantially the same plane as the apex of the blade 10]contained within the holder structure. It has been discovered that themaintenance of a maximum fall off angle from this apex is essential or,speaking in complementary terms, the included angle B of end members 102of FIG. 6 must be held to a minimum compatible with the strengthnecessary to apply the compressive forces to hold the blades in properalignment.

It has been found empirically that, using a 304 type stainless steelblade holder, this angle may be successfully limited to approximately15. It is hypothesized, however, that even a smaller angle may besuccessfully used if suitable material is utilized. However, the 15angle is found to supply satisfactory performance as well as anacceptable life during commercial deployment of the equipment. Aspreviously indicated, the effects of the geometric configuration of theholder are not understood. However, it is recognized that anymodification of electrode 20 configuration will alter the shape andpotential of the plasma and thereby affect the distribution and energiesof the sputtered target 57 material. The transverse sides or sidewallsof the holder are not presented in that no particular configurationseems to be needed except that the plane of these sides must fallsubstantially in the plane of the apex of the blades 101 and extend forsome reasonable distance around the periphery of the blade 101 stack. Itis significant to point out particularly with regard to the equipment ofFIG. 3 wherein dual facing electrode configurations are employed that acomplementary form of the blade holder shown in 102 may be provided tostack a second set of single-edge blades 101 in contraposition to thatshown in FIG. 6, thereby providing for contemporaneous sputtering ofboth edges as the holder is disposed between oppositely facing targetelectrode combinations. Similarly a blade holder of substantially thesame geometric configuration with the bottom planar member eliminatedmay be used to hold double-edge blades for simultaneous sputtering ofboth edges in the same dual electrode configuration.

Returning now to the novel process of the applicants and its performancewithin the confines and context of the sputtering equipment of FlG. 2,the razor blade, after cleaning in conformance with the process step 2of HO. 1, and it might be noted that as soon after this step aspossible, the blades are disposed either singly or in stackedarrangement as shown in FIG. 6 within the vacuum chamber 58 and rigidlyattached to the substrate electrode 20, thereby forming a part of suchsubstrate electrode 20. The target material 57 required for Deposition lis then adequately fixed to the surface of the electrode 56. Uponsealing of the vacuum chamber 58 and subsequent to its purging bynitrogen through the nitrogen vent unit 39, the chamber is evacuated bya suitable pump configuration (not shown). The pumping configuration maycomprise mechanical roughing pumps for first reducing the internalpressure of the chamber 58 to the range of Torr and in addition mightthen include turbomolecular pumps, diffusion pumps, ion pumps orcryo-pumps together or in combination to further reduce the internalworking pressure of the chamber 58 to a level of approximately 10 Torr,which, under normal circumstances, is considered compatible with RF orin fact most sputtering processes. Upon reaching the desired level ofvacuum as previously indicated, approximately 10 Torr, Argon is admittedto the chamber thereby lowering the vacuum level to betweenapproximately 1 2 (10) Torr. With the application of RF energy throughthe RF generator 31 and the matching unit 33 and the switch S position1, a plasma is established between the electrodes and a negative selfbias forms on the substrate electrode 20. Once the plasma has formed,the energetic collisions of the plasma electrons with the Argon gasmolecules causes the formation of positive Argon ions which, aspreviously indicated in this application, are attracted toward thesurface of the substrate electrode 20. Upon their impingement on theblade edges, the apex of which are disposed toward the electrode 56,there is a resultant dislodgement of material both blade steel as wellas contaminants thereon from the blade edges. This process is continuedfor a predetermined period of time commensurate with operationalconditions determined to some extent by the blade material utilized andthe cleanliness of the blade edges after the cleaning process step 2.Typical ranges of time for the completion of this, what is known asetching or sputter etching, process varies between 3 and 10 minutes.Other typical values involved in this sputter etching step is theapplication of between 300 and 800 W. of RF power with approximatelyzero refracted power and the development of approximately a thousandvolt or 1 KVDC self bias on the substrate electrode 20. Of course,during this time, the coolant unit 26 is maintaining the electrodes at adesirable temperature compatible with the material used and theallowable range of temperature within the vacuum chamber 58.

After performing this sputter etching of the blade holder razor bladecombination located on the substrate electrode 20, the switch S is movedto its second position in which the RF energy is applied to theelectrode 56 while the substrate electrode 20 is connected to systemground. Again, with the shutter still maintained in its interposedposition between the electrodes 56, 20, the plasma is again establishedat an Argon or vacuum pressure of normally higher value, typicallybetween 5 and 7 (10) Torr. The power level is raised to a higher value,typically in the range of 1.5 KW of real power, and the bias reaches aconsiderably higher level, typically in the range of 2 KVDC negative. Inthis circuit configuration, the development of a negative self biasvoltage on the electrode 56 now attracts the positive Argon ionsgenerated within the plasma toward the target 57, resulting in asputtering of material, both target material and contamination from thesurface of the target 57. This results in a pre-cleaning of the targetprior to performance of the actual sputter deposition process onto therazor blades contained in the substrate electrode 20. Typically thispre-cleaning operation is continued for a short interval ofapproximately 1 minute. Further pre-cleaning or pre-cleaning for alonger time is not normally considered necessary when the targetmaterial is substantially pure and kept in a clean environment' Withproper manipulation of the control unit 55, the shutter is then removedfrom between the electrodes contained in the vacuum chamber 58, therebyexposing the surface of the target 57 to the apex of the blades disposedon the substrate electrode 20. At this juncture, the material sputteredfrom the surface of the target 57 is allowed to impinge upon and coatthe razor blade edges properly disposed toward the electrode 56. Sincethe essential configuration of the internal vacuum chamber circuitry isnot altered or greatly altered by the removal of the shutter 53, theworking parameters of the sputter deposition step remain essentially thesame as that of the pre-clean step, i.e., the pressure level ismaintained in a range approximately 5 7 (10)" Torr, the real RF power isapproximately 1.5 KW, and the self bias negative voltage developed onthe electrode 56 is approximately 2 KVDC. The period of sputterdeposition is, of course, varied greatly depending upon the materialforming the target 57 as well as the desired thickness of coating. Manymaterials display widely variant sputtering rates depending upon thestructure or morphology of the target 57 as well as the work function ofthe material utilized. Typically depending upon the target 57 material,the sputter time may vary between 1 and 15 minutes.

The chamber 58 is vented by the nitrogen vent unit 39 by the admissionof nitrogen gas to the chamber through a needle valve connection. Oncethe chamber is vented to approximately atmospheric pressure, the chamber58 is then opened and the target material 57 is changed to the materialwhich is to be used in the Deposition ll step. As previously indicated,the preferred material is a pure chromium. Normally the purity of thischromium target is maintained in excess of 99.99 percent. However, lesspure targets may be utilized without detracting from the quality ofperformance and the results of the novel process. of the applicants. Thenew target material 57 is attached to the electrode 56 in the samemanner as the previous refractory target material for the Deposition Istep. It may well be timely to point out that a chamber 58 constructedto have more than one electrode target configuration may be constructedto perform the process outlined herein. If

dual targets were arranged and could be properly indexed, the subsequentcoating applied in the Deposition [I step may be deposited without theneed for opening the chamber and changing the target material. It isalso noted that the substrate and shutter combination 20 and 53respectively may be indexed to a different location and placed therebyunder a different target material as opposed to indexing or changing theelectrode configuration which may cause some problems or difficultiesassociated with the RF connections.

After changing the target material to chromium, the chamber 58 is againsealed and the steps preparatory to sputter deposition are repeated withthe exception of the surface preparation 10 step, i.e., the sputteretching of the substrate 20 prior to sputter deposition. obviously, thesurface coating applied during the sputter Deposition I step need not besputter etched prior to a subsequent deposition in that the materiallaid down on the surface is substantially pure and free ofcontamination. Briefly, the chamber 58 is purged by dry nitrogensupplied to the chamber 58 by the nitrogen vent unit 39; the pump unit58' then evacuates the chamber to a level of approximately 10 Torr;Argon is then admitted to the chamber 58 through the Argon 25 unit to apressure of between 7 (10) Torr and, of course, the coolant unit 26continues to supply a cooling fluid through the appropriate RFelectrodes. With switch S in position 2, RF energy is applied to theelectrode 56 with the shutter 53 disposed between the substrate and theelectrode. The power levels are adjusted to approximately 1.4 KW and theself bias voltage developed is approximately 2 KVDC. Using theseoperative parameters, the new target 57 is pre-cleaned for a period ofapproximately 1 minute.

After completion of the pre-clean step, the target 57 is exposed to thesubstrate 20 by removal of the shutter 53 through operation of theshutter control unit 55. With the vacuum level in a range betweenS-S(10) Torr, the substrate 20 is then sputter deposited with the target 57chromium material for approximately 1 minute. Under these controllingconditions, a coating of chromium approximately Angstrom units inthickness is applied to the substrate 20 principally falling upon orimpinging upon the cutting edges of the blades contained integrallywithin the substrate electrode 20. As heretofore indicated, this periodof sputtering may be prolonged for a greater time if a thicker coatingof chromium material is desired to the extent that such thicknessdimension is compatible with the desired cutting edge sharpness of theblade which is determined through various test equipment well known tothose ordinarily skilled in the razor blade art. One well establishedtest for the determination of sharpness is the cutting of nylon fibersdisposed on a moving belt at a certain angle to the razor blade cuttingedge. A measurement of the cutting forces involved in this test providesacceptable data to a determination and correlation of edge sharpness.Normally, or at least under most circumstances, the final radius ofcurvature of the cutting edge of a razor blade is approximately in the400 Angstrom range. This radius provides a relative indication of theallowable total thickness of thematerial provided by the combination ofthe sputter Deposition I step and the sputter Deposition II step.Certainly, greater than a total thickness in the range of 500 Angstromunits may not be acceptable.

After completion of the Deposition ll step, the chamber 58 is againvented through the nitrogen vent unit 39 and opened to the atmospherefor removal of the blades. The blades are then spray coated or otherwisecoated with the appropriate lubricious material, normallypolytetrafluoroethylene, and subjected to the thermal process necessaryto provide a final adherent coating. This thermal process mainlyinvolves the evolving from the dispersion of the volatile mediumsnecessary to the application of the PTFE constituents. The temperatureof the heating process in addition to boiling off or evaporating thevolatile medium raises the PTFE dispersed particles to approximatelytheir fusion temperature so that in essence the PTFE is sintered to thesurface forming an approximately continuous coating over the ultimateapex of the razor blade edge and the facets or intersecting surfacesforming such apex.

FIG. 5 demonstrates in typical cross-section a razor blade of distorteddimension and form showing the final product having thereon the materialcoatings applied during Deposition l, ll and Ill steps. The blade is ofthe single-edge type having a height from base to ultimate apex orcutting edge of H. The cutting edge is shown as formed by twointersecting surfaces having an included angle A therebetween. Inaccordance with products actually sold and used today, theseintersecting surfaces actually comprise a number of facets havingdifferent included angles, only the final facets having the same angle Aas depicted for the intersecting surfaces of FIG. 5. Normally, all thefacets and to some extent the body of the blade 101 is covered with thevarious coatings comprising the novel process of this application.However, it is not necessary for performance that these coatings doextend beyond the facets of the blade.

The first coating applied to the blade designated as l conforms to thematerial applied or deposited during the Deposition I step. This sputterdeposited coating is normally the refractory material previouslymentioned or as also indicated some other material which may havedesirable blade characteristics but which does not have the ultimateadherence to PTFE coating. The thickness of this coating as it wrapsabout the ultimate edge of the blade is usually chosen to be between 200and 300 Angstroms, appreciating, however, that this thickness may beradically changed if different blade edge characteristics are desired,such as increased or decreased blade sharpness. The coating designatedas ll correlates with the Deposition ll step and as indicated normallyis a chromium coating. Although this coating is shown as havingessentially the same thickness as l and Il coatings, it is noted thatthis thickness is normally in the range of 25 Anstrom units which, on arelative scale, would be impossible to show within the drawing of FIG.5. Thus, for demonstration purposes, the same thickness coating isshown. The lll coating is that placed on the blade during the Depositionlll step. As indicated, normally this coating is applied by a spray withsubsequent heating for formation of a substantially continuous anduniform coating. However, as indicated in copending Application Ser. No.680,794, filed Nov. 6, 1967, now U.S. Pat. No. 3,635,811, dated Jan. 18,1972, this final lubricious coating may also be applied by a sputteringprocess which may be performed in the same chamber 58 and with the sameequipment as shown in FIG. 2. Of course, if such final lubriciouscoating is to be sputtered, the target material 57 as well as theoperating parameters of the chamber must be significantly modified.Since this final lubricious coating III is of greatly increasedthickness in the range of 2,000 Angstrom units and considerably higher,its thickness as shown in FIG. 5 is greatly distorted in order to showthe coating without having to scale the razor blade and coatings I andII to relative dimensions not capable of demonstrating the points ofmost interest with respect to the conformation of the final product.FIG. 4 shows a plan view of blade 101 indicating that the coatingsextend substantially continuously throughout the entire expanse of thefinal facets of the razor blade edge.

To better demonstrate the applicability of the novel process presentedherein and to provide a clearer understanding of both the equipment andthe various steps employed, the following examples are presented:

EXAMPLE 1 Standard double-edge stainless steel razor blades ofapproximately 0.004 inch thickness were cleaned in accordance with thecleaning step 2 and mounted within a vacuum chamber substantiallyconforming to that depicted in FIG. 2, and this example and thefollowing examples will be discussed in the context of the equipment asshown in FIG. 2. A single edge of the doubleedge blades are disposed onthe substrate electrode in facing relationship to electrode 56 and thetarget 57.

Sputter Deposition I Target 57 material Target dimensions A rgonpressure Linde synthetic sapphire comprising essentially hexagonalcrystal lattice structures of AL O manufactured by the Linde CrystalProducts Division of Union Carbide 4" in diameter by V4" thick between 57 n0)- Torr RF power 1.4 KW Self bias voltage 2.2 KVDC Sputter timeapproximately 7-56 min.

Sputtering rate Coating thickness Sputter Deposition ll Target 57material Target pre-clean step Argon pressure approximately 30 Angstromsper min. between 200 and 300 Angstrom units Pure chromium between 5 7l0) Torr RF power 1.4 KW Self bias electrode voltage 2.2 KVDC 60 Periodl minute Sputter deposition step Argon pressure between 5 7 10) TorrPower 1 KW Self bias DC voltage 2.2 KVDC Time l0 seconds Sputter rateCoating thickness approximately Angstrom units per min. approximately 30Angstrom units Thereafter Deposition Ill step was performed and acoating of PTFE was applied to the blade surface. Standard tests showedthe blade to display a low coefficient friction and an increased wearlife.

EXAMPLE 2 The conditions of Example 1 were repeated in Example 2 withthe exception of the sputter etch time, which was reduced from a5-minute interval to a l-minute interval. Identical results wereobtained with regard to performance of the ultimate product afterapplication of the final lubricious coating of PTFE.

EXAMPLE 3 The equipment was set up in the same manner as Examples l and2. The blade edge was sputter etched under the following conditions:

RF power 200 W. Argon pressure 1 (l0)' Torr Self bias voltage l KVDCSputter etch time 5 min. Target pre-clean step Target material quartzArgon pressure RF power Pre-clean time Self bias voltage SputterDeposition I step Argon pressure Same as Example Same as Example Same asExample Same as Example Same as Example I RF power Same as Example ITime Same as Example 1 Self bias voltage Same as Example 1 Thicknessapproximately 200 Angstrom units Sputter Deposition II step Targetmaterial Pre-clean conditions Same as Example I Same as Example I Sameas Example 1 Same as Example 1 approximately 30 Angstrom units The bladeof this example performed in a similar manner'to that produced underExamples 1 and 2 and similarly displayed improved friction and lifecharacteristics. Note: Throughout Examples 1 3, a Bendix 6 inchesdiffusion pump system with a liquid nitrogen baffle was used to producethe desired vacuum levels, and throughout the three examples thedistance from the target to the blades was approximately 2 inches.

As clearly demonstrated by the foregoing disclosure, razor bladesdisplaying improved shaving characteristics may be produced by theoutlined methods and the indicated examples. Processes performed inconformance with the foregoing teaching will produce blades meeting and,in some instances, greatly exceeding the qualities of razor bladespresently used by the public. Although the equipment shown in FIG. 2 maybe ,uti-

lized in production facilities, particularly if modified to contain morethan one target and/or more than single blade holding fixtures withcommensurate indexing equipment, this type of equipment is not bestsuited to the high production needs of a large blade manufacturingconcern. When considering that in excess of two to three million bladesa day must pass through and be subjected to the process outlined in FIG.1, it can be appreciated that any equipment design intended to enhancethe speed of the process and therefore the ultimate output of finishedblades is of considerable value and importance. In this regard, it isnoteworthy to point out that the addition of certain reactive gases, forexample, oxygen, to the sputtering chamber during the refractory sputterdeposition steps will under proper conditions greatly increase thesputtering rate and thereby reduce the total sputtering time needed. Anyreduction of this nature in the time required for the total processperformance when involved in the production of literally millions ofblades is of significant import to the overall cost of production of theproduct. FIG. 3 shows equipment peculiarly suitable to the manufactureof razor blades in accordance with the novel process of the applicants.This equipment permits the continuous sequential batch processing ofalarge quantity of blades while maintaining extreme limits of cleanlinessfor the targets and the chambers utilized and further limiting the needfor continuous pump-down of the sputter deposition chambers prior toentry of the product into the chamber and subsequent to exit of theproduct from the chamber.

FIG. 3 shows an exemplary embodiment of an equipment configurationprimarily designed for the continuous batch processing of razor bladesin conformance with the applicantss process. Chambers 10, ll, 12 and 24'constitute the vacuum chambers necessary for completion of the process.These chambers are joined by vacuum interlocks 21, 22 and 23 betweenchambers 10, 11 and 12 and 24 respectively. Entrance vacuum and exitvacuum interlocks 21 and 24 are provided for entry of the blades intovacuum chamber and exit of the blades from vacuum chamber 24'respectively. Associated with each chamber is a vacuum system designatedas Pump A 27, Pump B 28, Pump C 29, and Pump D 30, which pumps must becapable of producing vacuum levels commensurate with the performance ofthe process, which levels were previously outlined in the foregoingdisclosure and Examples 1 3. The blade substrate is shown as movingsequentially through the chambers until its final exit from chamber 24through the vacuum interlock 24. It is important to note that in acontinuous batch system, there is always present in any given chamber abatch of blades mounted on the substrate electrode 20 and only at thebeginning and end of any continuous production run are any of thechambers without such blade batch.

Chamber 10 shows within its structure two electrodes 42, 42' surroundedby RF shielding 45, 45 respectively. The two electrodes 42, 42' areprovided for the continuous preparation of both edges of double-edgeblades or of single-edge'blades mounted back-to-back on the substrateholder 20. This contemporaneous treatment of two edges greatly minimizesthe time necessary for completion of the process. Vacuum chamber 10comprises the station in which the sputter etching of the razor bladeedges is performed, thereby confining the release of contaminants andthe removal of blade edge material to a single chamber thusly preventingany effect of such contamination on the deposition steps of the process.The substrate electrode 20 is shown as connected to the matchingimpedance unit 33 and is surrounded by an RF shield 49. Vacuum chamber11 similarly contains two RF electrodes 43, 43' surrounded by theirrespective shields 46, 46. The substrate holder 20 is tied to thechamber 11 wall by means of line 51, which chamber 11 is brought tosystem ground as are all the chambers of the system, namely, chambers10, ll, 12 and 24. In the instance of chamber 11 both RF electrodes 43,43' are brought to the matching unit 33 to provide for their RF powerexitation. This is contrary to chamber 10 where the two electrodes 42,42are brought to the chamber walls by line 50 and 50' respectively, whichwalls are, as previously indicated, brought to system ground. Targets40, 40 are shown as fixed to the RF electrodes 43 and 43' respectivelyin the same manner as the target 57 was attached to the RF electrode 56in FIG. 2. This chamber 11 is used for the performance of the Depositionl coating and thusly the targets comprise the refractory material orother material to be first applied to the blade edge in order to obtaincertain desirable blade characteristics. Proceeding to chamber 12 thereis shown a similar equipment arrangement as chamber 11. Mounted in thechamber are RF electrodes 44, 44 with their respective RF shields 47,47'. Affixed to the face of each electrode are targets 41, 41 comprisingthe material to be applied in the Deposition ll step, i.e., the chromiummaterial or other material displaying the necessary adherence to boththe PTFE final lubricious coating and the prior coating applied duringthe Deposition I step. The substrate electrode 20 is brought to thechamber wall by means of line 52 while RF power is sent to theelectrodes -by means of connections 37 and 38. in all instances, properRF connectors and the necessary seals to maintain vacuum are employed tobring lines and connections in and out of the vacuum chambers. Finallywe proceed to chamber 24' which is devoid of internal electrodestructure as it is only used for an equipment removal purpose. The useof a separate removal vacuum chamber 24 provides for a maintenance ofcleanliness in both vacuum chambers ll, 12 as well as a minimization ofvacuum pump-down time. The vacuum interlock members 21, 21, 22, 23, 24essentially comprise sliding valve doors which permit passage of theblade holding members to proceed into and through the sequentialchambers until their ultimate exit through the last chamber 24'. It isfurther important to note at this time that an additional chamber may beinserted between chambers 12 and 24' for sputtering of the lubriciouscoating if such process step is to be employed, but it is pointed outthat the means of application of the lubricious coating is not anessential part of the novel contribution of this invention but rathersimply constitutes the process step necessary to the conformation of theultimate product.

The radio frequency energy again comprises a 13.56 megacycle supply andprovides the energy necessary for the electrodes 43, 43', 47, 47' andfor substrate electrode 20 in chamber 10. Lines 34-38 are previouslyindicated supply the RF power to the previously mentioned electrodes andthe substrate electrode 20. The switching unit 32 serves to interruptthe RF power supplied by the radio frequency generator 31 when desiredand to further either apply RF energy to the various lines or tointerrupt it when the particular step of the process so requires. Tobriefly describe the function of the switching unit, it is pointed outthat during the sputter etching step performed in vacuum chamber 10 RFenergy is applied to line 34. When the sequential deposition steps areperformed in chambers 11 and 12, then the same RF power is applied tothe appropriate lines 34-38. The matching impedance unit 33 constitutesseparate impedance matching units for each of the electrodes involved inthe process. No doubt this unit might comprise one single. matching unitwith various lines or taps brought to the lines 34-38 but, however, itis found most economical and simpler of construction to provide aseparate impedance matching unit within the confines of the unit 33 toindividually match each of the electrodes during the process stepinvolved.

The DC meter unit 48 is used to monitor the self bias voltage developedduring the radio frequency sputtering process on each of the lines34-38. As heretofore indicated in the specification, each of theelectrodes associated with the numbered RF power lines will develop aself bias voltage depending upon the level of power applied and otheroperating parameters of the system. In addition to the external unitsnow mentioned necessary to the batch process system of FIG. 3, there isalso provided for similar purposes as previously outlined with respectto the equipment of FIG. 2 a nitrogen vent unit suitable to purging thechambers and for raising the vacuum level prior to opening of thechambers after evacuation. Argon unit 25 is further provided to supplythe ionizable gas to each of the chambers involved in the sputteringprocess, namely, chambers 10, ll and 12, and. finally a coolant unit 26passes either water or some other cooling fluid such as ethylene glycolto'properly cool the RF electrodes and other members which may besubject to heat problems during the performance of the steps necessaryto producing the desired coatings on the razor blade edge.

Briefly to consider the equipment of FIG. 3 in an operational sequence astack of razor blades held in a fixture similar to that shown in FIG. 6only deploying blades in opposite directions so that both edges of theblades, in the case of double-edge blades, or complementarily facingblades in the case of single-edge blades 10], are exposed to thesputtering or sputter etching electrodes. The first batch of blades isintroduced to the chamber 10 through the vacuum interlock or slide valve21. Once within this chamber the entire system of chambers 10, ll, 12and 24' are reduced in vacuum level to approximately 10' Torr. Argon isy then admitted to vacuum chamber 10 by means of the Argon unit 25which, with the application of RF energy to line 34, results in theformation ofa plasma and sputtering of material and contaminants fromthe exposed edges of the razor blades takes place. Upon completion ofthis sputter etching operation, vacuum chamber 10 is again pumped downto its 10 Torr level and the vacuum interlock valve 21 is opened toallow for passage of the razor blades by means of suitable carriersthrough to vacuum chamber 11. Similar to the justdescribed sequence ofoperation for the sputtering etching of the blades in chamber 10, Argonby means of Argon unit 25 is admitted to the vacuum chamber 11 with theapplication of RF energy to the lines 35, 36. Again, a plasma results.However, in this instance, since the electrodes 43, 43' and theirtargets 40 and 40 respectively are now brought to the RF power, thesputtering takes place from the target onto the blade edges. Since theelectrodes to which RF energy is applied take on the negative selfbiasing voltage, the positive ions created in the plasma by collisionswith the energetic electrons are attracted toward the targets 40, 40,thereby causing the removal of material from their surfaces and theirresultant energetic deposition upon the intersecting surfaces formingthe blade edges. Once again the chamber 11 is evacuated to the 10" Torrrange and the associated vacuum interlock valve 22 is opened for passageof the blades through to the chamber 12.

The same steps are performed in chamber II for the Deposition 1 processare repeated in chamber 12 for the Deposition II process, therebyresulting in a blade having two coatings placed over its ultimate edgeand the facets or surfaces forming such ultimate edge. Subsequent tothis last sputter deposition step, chamber 12 is evacuated to the 10Torr level and the blades are passed through vacuum interlock valve 23to the last chamber 24. It should be pointed out at this time that eachof the valves 21, 21 22, 23 close after passage of the blades through tothe next chamber. With the blades in vacuum chamber 24' this chamber isvented by means of the nitrogen vent unit 39to atmospheric level andvacuum interlock valve 24 is opened for removal of the blades from thesystem. As previously pointed out, as blades are removed from onechamber to the next, new blades are being introduced from the chambergoing before, thus constituting a continuous batch sequential processingsystem. The operating parameters, i.e., vacuum, time, power, self biasvoltage, are substantially the same as those indicated in Examples 1-3and the description going before such examples, the difference beingthat each step in the operation is performed in a separate chamberrather than a single chamber requiring frequent opening and closing ofthe system with resultant susceptibility to contamination. Operation ofequipment such as this is well known to those individuals ordinarilyskilled in the art once the essential operating parameters andconditions are brought to their attention. It is pointed out that US.Pat. application Ser. No. 861,937, filed Sept. 29, I969, adequatelydescribes and discloses a system appropriate to the carrying out of thecontinuous batch process herein disclosed. It would be only necessary toalter the target materials and operating parameters to conform to thosenovel aspects of the applicant's invention.

In considering both the continuous batch process of FIG. 3 and thesingle batch operating equipment and procedure demonstrated in FIG. 2,it is important to indicate its applicability to band razor blades,which comprise continuous strips of predetermined length commensuratewith a certain number of shaving edges normally provided on discreetlydimensioned razor blades. In use, such continuous strips are indexed acertain length substantially equaling a single-edge length ofa discreetdimensioned razor blade. When depositing coatings, or, more precisely,sputter depositing coatings, on such edges a long continuous length ofband razor blade is utilized, often comprising lengths constitutingmiles or substantial portions of miles in length. A copendingapplication Ser. No. 144,510, filed May l8, 197 l describes a singletarget electrode configuration capable of sputter depositing coatings ona band razor steel blade. However, due to the limited dimensions of thetarget, the band blade must be rotated under the target during thesputtering process, thusly seriously hampering the efficiency and outputof the process. While the equipment of FIG. 2 would still requirerotation of the band razor under the target 57 in order to obtain areasonably uniform and continuous sputter deposit coating dueprincipally to the limitations on dimensions of such chambers, thecontinuousbatch system of FIG. 3 is capable of much more efficientoperation with respect to this type of razor blade.

FIGS. 7, 8 and 9 show an exemplary fixture capable of holding continuousstrips of band blade during the sputtering process. Due to the largetarget configurations which may be employed in the chambers 10, ll, 12of the continuous batch system, it is possible to place a completespiral of band razor steel in facing relationship to the sputteringtargets, thereby obviating the need for rotation of the blade edgetransversely across the face of the target during the sputtering processor operation. It has been found to be most advantageous to place in thefixture shown in FIGS. 7, 8 and 9 more than a single spiral of bandrazors and to place them in oppositely facing directions so as to takeadvantage of the dual electrode configuration of FIG. 3. Thusly, it ispossible to greatly increase the efficiency and improve the uniformityof the sputtering process on band razor blades in that a total of fourstationary spirals may be coated at one time as opposed to a singlespiral being rotated beneath a target as previously or heretoforeutilized. The fixture for holding the band razor strip constituting twonests into which the strip is placed in spiral configuration, whichnests are then clamped together in oppositely facing directions by meansof a ring clamp. It has been found that the nesting of the bladesexposing no more than 0.005 of an inch over the upper surface of thenest holder 1 10 is essential to providing a uniform coating on thesurfaces forming the blade edge. It has also been determined that whileof less criticality than the exposure of the edge of the upper surface110, the dimensions of the inner hub indicated by diameter D1 and theouter hub indicated by diameter D2 are of significance. Generally it ispreferred that the diametrical distance from the outside of theperiphery formed by diameter D2 to the outermost edge of the bladespiral should most appropriately be between one and two inches and thatthe inner hub be approximately between 5 and 9 inches in diameter. Ofcourse, these dimensions may be altered depending upon the amount ofblade steel desired to be contained in the blade spiral and thedimensions of the sputtering chambers. The nests 110 in combination withthe band clamp 111 are in turn captured within a second fixture 1 12 foractual placement within the continuous batch system. The holder 112 isthen carried by appropriate motion drives through the various chambersfor application of the desired coatings.

Referring to Example 1 heretofore set forth, it has been found that thematerial sputtered upon the substrate surface in the Deposition I stepcomprises a crystalline structure of hexagonal lattice form having apreferred orientation. It has also been found through the application ofmicroprobe analysis, i.e., the examination of emitted X-rays uponsubjection of the material to an electron beam, that the materialconstitutes in its elemental forms pure A1 0 within the precision limitsof the microprobe equipment. Relating these two factors as to themorphology of the coating and the purity of the constituents, thematerial sputtered from the target 57 onto the substrate apparentlyconstitutes the same synthetic sapphire of which the target is composed.Thus, in addition to disclosing a novel method for the application ofrefractory materials to razor blades or, more generally, cutting edgesand the subsequent preparation of such surfaces for the lubriciousmaterial, there is further presented in accordance with the invention anovel process for applying a coating of corundum or synthetic sapphireto the surface of a substrate. While not fully understanding themechanism of this material transfer by means of sputter deposition, itis presumed that the energies of the atomic size particles or moleculesremoved from the surface of the target 57 are within the range necessaryto bring about the desired crystalline formation on the surface of thesubstrate. Thus, there is completely transferred to the substrate thecharacteristics of the refractory target material commensurate with athin film formed of such material. Thus, this wholly unexpected resultof the described blade manufacturing process finds ready appli cationfor other purposes. It would now seem possible to transfer sapphire orother material through sputter deposition means from a target to asubstrate, which substrate may comprise any equipment on which suchrefractory coatings would be suitable either for wear, dielectric orother suitable and appropriate reasons.

It is apparent that the blade material may be composed of material suchas carbon steel, chromium steel, tungsten steel, molybdenum steel orchrome-nickel steel. Further, it is obvious that the blade material maybe an alloy containing material selected from the group consisting ofstainless steel, carbon steel, chromium steel, tungsten steel,molybdenum steel, and chromenickel steel.

In summary, the disclosure of this application has set forth a novelprocess for the production of razor blades, or more generally speakingcutting edges,.having wholly unanticipated and unpredictable qualities.[t is emphasized that the teachings of this disclosure are intended tobe illustrative and exemplary of the invention and not to be delimitingof its scope. Thus, it is intended that those variations andmodifications of the novel process and products produced thereby whichwould become obvivous to one ordinarily skilled in the art are to beconsidered within the scope and ambit of the applicants invention.

What is claimed is:

l. A method of making a razor blade comprising the steps of:

forming a blade from a suitable material, the blade having an elongateedge comprising two intersecting surfaces;

sputter depositing on the edge a first coating of refractory material;

coating the edge with a second material displaying adhesion to asubsequent coating of lubricious material and to the refractorymaterial; and then coating the edge with the lubricious material.

2. The method of claim 1 wherein the first coating is RF sputterdeposited and the second material is sputter deposited.

3. The method of claim 2 wherein the refractory material is corundum.

4. The method of claim 2 wherein the refractory material is selectedfrom the group consisting of glass, corundum, quartz, alumina, beryllia,silicon carbide, boron nitride, and tungsten carbide.

5. The method of claim 4 wherein the refractory material comprisesalloys and mixtures of materials selected from the group.

6. The method of claim 2 wherein the refractory material is syntheticsapphire.

7. The method of claim 1 wherein the total thickness of the depositedrefractory material and the second material is limited to that necessaryto maintain a desired degree of edge sharpness.

8. The method of claim 7 wherein the total thickness is approximately500 Angstrom units.

9. The method of claim 7 wherein the thickness of the refractorymaterial is approximately 300 Angstrom units and the thickness of thesecond material is approximately 25 Angstrom units.

10. The method of claim 2 wherein the RF sputter depositing comprisesthe steps of:

disposing the blade in an evacuated chamber having an electrode on whichis mounted a target of refractory material;

introducing into the chamber an ionizable gas and establishing a plasmaby imposing an RF potential between the electrode and the blade;

depositing on the edge particles dislodged from the target byimpingement of gas ions formed in the plasma upon collision of RFexcited electrons and the ionizable gas molecules.

11. The method of claim 10 wherein the chamber is evacuated toapproximately l Torr and the ionizable gas is introduced to a pressureof approximately between and s '10 Torr.

12. The method of claim 11 wherein the refractory material is syntheticsapphire, the ionizable gas is Argon and the blade is positionedapproximately 2 inches from the target, the edge apex being disposedsubstantially in a plane parallel to the target and the refractorymaterial is deposited at a rate of approximately 30 Angstroms per minutefor a period between approximately 5 and minutes.

13. The method of claim 12 wherein the frequency is 13.56 MC and whereinthe blade is sputter etched prior to deposition of the refractorymaterial and a shutter is interposed between the target and the bladeduring the step of sputter etching.

14. The method of claim 13 wherein capacitor means is serially connectedbetween the blade and the RF potential and the shutter is connected toground during sputter etching and wherein when the shutter is removed,the RF potential is connected to the electrode and the blade isconnected to ground for sputter deposition.

15. The method of claim 14 wherein the target is precleaned prior tosputter etching and wherein during pre-cleaning the shutter isinterposed, the RF potential connected to the electrode and the shutteris connected to ground.

16. The method of claim 15 wherein the following parameters aremaintained during pre-cleaning, sputter etching and sputter deposition,respectively:

Power approximately 400 W.

1.4 KW and L4 KW; approximately I KVDC 2.2 KVDC and 2.2 KVDC andapproximately 5 min.,

l min. and between 5 and 10 min.

Self bias electrode voltage Time 19. The method of claim 18 wherein thesecond material is deposited to a thickness of approximately 25 Angstromunits and the second material is a metal containing material.

20. The method of claim 19 wherein the second ma terial is selected fromthe group consisting of chromium, platinum, aluminum, titanium and iron.

21. The method of claim 19 wherein the second material comprisesmixtures and alloys of metals selected from the group consisting ofchromium, platinum, aluminum, titanium and iron.

22. The method of claim 19 wherein the second material is chromium.

23. The method of claim 19 wherein the lubricious material is a polymermaterial.

24. The method of claim 23 wherein the polymer is selected from thegroup consisting of polytetrafluoroethylene, polypropylene,polyhexafluoropropylene, polychlorotrifluoroethylene and polyethylene.

25. The method of claim 23 wherein the lubricious material comprisescopolymers and telomers of polymers selected from the group consistingof polytetrafluoroethylene, polypropylene, polyhexafluoropropylene,polychlorotrifluoroethylene and polyethylene.

26. The method of claim 23 wherein the polymer ispolytetrafluoroethylene.

27. The method of claim 6 wherein the lubricious material is sputterdeposited onto the edge.

28. The method of claim 27 wherein the lubricious material is depositedto a thickness of at least 1,000 Angstrom units.

29. The method of claim 17 wherein the edge is sputter etched in a firstvacuum chamber, the blade is moved through a vacuum interlock to asecond vacuum chamber in which the edge is sputter deposited with therefractory material, the blade is then moved through a second vacuuminterlock to a third vacuum chamber in which the edge is sputterdeposited with the second material, and finally the blade is movedthrough a third vacuum interlock to a fourth vacuum chamber which isthen vented to the atmosphere to permit blade removal for subsequentcoating with the lubricious material.

30. The method of claim 29 wherein blades are continuously sequentiallypasses through the chambers.

31. The method of claim 1 wherein the refractory material comprises analuminum oxide compound formed on the elongate edge when materialsputtered from an aluminum target combines with oxygen present in theenvironment.

32. The method of claim 10 wherein the sputtering rate is increased bythe presence of a reactive gas.

33. A cutting instrument comprising: an elongate edge of narrow includedangle formed by two intersecting surfaces of a refractory material,

an overlay coating of material over the edge for providing adhesion tothe refractory material and a lubricious material, and

a final coating of the lubricious material.

34. The cutting instrument of claim 33 wherein the refractory materialand the coating are sputter deposited on the edge.

35. The cutting instrument of claim 33 wherein the refractory materialis synthetic sapphire.

36. The cutting instrument of claim 34 wherein the refractory materialis selected from the group consisting of corundum, alumina, glass,quartz, beryllia, silicon carbide, tungsten carbide and boron nitride.

37. The cutting instrument of claim 35 wherein the refractory materialis RF sputter deposited on the edge.

38. The cutting instrument of claim 37 wherein the overlay coating is RFsputter deposited.

39. The cutting instrument of claim 38 wherein the lubricious materialis RF sputter deposited.

40. The cutting instrument of claim 37 wherein the total thickness ofthe refractory material and the overlay coating does not exceedapproximately 500 Angstrom units.

41. The cutting instrument of claim 40 wherein the thickness of therefractory material is approximately 300 Angstrom units and thethickness of the overlay coating is approximately 25 Angstrom units..

42. The cutting instrument of claim 41 wherein the intersecting surfacesare honed surfaces and the narrow included angle is less thanapproximately 30.

43. The cutting instrument of claim 42 wherein the narrow included angleis approximately 44. The cutting instrument of claim 43 wherein thecutting instrument material is stainless steel.

45. The cutting instrument of claim 43 wherein the cutting instrumentmaterial is selected from the group consisting of stainless steel,carbon steel, chromium steel, tungsten steel, molybdenum steel, andchromenickel steel.

46. The cutting instrument of claim 43 wherein the cutting instrumentmaterial is an alloy containing material selected from the groupconsisting of stainless steel, carbon steel, chromium steel, tungstensteel, molybdenum steel, and chrome-nickel steel.

47. A method for applying a lubricious material to a cutting instrumenthaving an edge formed by two intersecting surfaces of a refractorymaterial having limited adhesion to the lubricious material comprisingthe steps of:

sputter depositing on the edge an overlay coating displaying adhesion tothe lubricious material; and then coating the edge with the lubriciousmaterial.

48. The method of claim 47 wherein both the refractory material and theoverlay coating material are sputtered on the edge and the refractorymaterial is synthetic sapphire.

49. The method of claim 48 wherein both the refractory material and theoverlay material are RF sputtered on the edge.

50. The method of claim 49 wherein the refractory material is selectedfrom the group consisting of glass, quartz, corundum, alumina, beryllia,silicon carbide, tungsten carbide and boron nitride.

51. The method of claim 49 wherein the refractory material is analuminum oxide compound formed by sputter depositing aluminum in anoxygen atmosphere.

52. The method of claim 49 wherein the lubricious material is selectedfrom the group consisting of polytetrafluoroethylene, polypropylene,polyhexafluoropropylene, polychlorotrifluoroethylene and polyethylene.

53. The method of claim 52 wherein the lubricious material is sputterdeposited on the overlay coating.

54. The method of claim 49 wherein the overlay coating is a metalcontaining material.

55. The method of claim 54 wherein the metal is selected from the groupconsisting of chromium, platinum, titanium, aluminum and iron.

56. The method of claim 54 wherein the overlay coating is an alloycontaining metal selected from the group consisting of chromium,platinum, titanium, aluminum and iron.

57. The method of claim 54 wherein the overlay coating material ischromium.

58. The method of claim 54 wherein the overlay coating thickness isapproximately 25 Angstrom units and the total thickness of boththerefractory material and the overlay coating is limited to that necessaryto maintain a desired degree of edge sharpness.

59. The method of claim 58 wherein the refractory material coating isapproximately 300 Angstrom units in thickness.

60. The method of claim 32 wherein said reactive gas is oxygen.

61. The cutting instrument of claim 33 wherein the cutting instrument isa razor blade.

62. The cutting instrument of claim 35 wherein the cutting instrument isa razor blade.

63. The cutting instrument of claim 36 wherein the cutting instrument isa razor blade.

64. The cutting instrument of claim 37 wherein the cutting instrument isa razor blade.

65. The cutting instrument of claim 38 wherein the cutting instrument isa razor blade.

66. The cutting instrument of claim 40 wherein the cutting instrument isa razor blade.

1. A method of making a razor blade comprising the steps of: forming ablade from a suitable material, the blade having an elongate edgecomprising two intersecting surfaces; sputter depositing on the edge afirst coating of refractory material; coating the edge with a secondmaterial displaying adhesion to a subsequent coating of lubriciousmaterial and to the refractory material; and then coating the edge withthe lubricious material.
 2. The method of claim 1 wherein the firstcoating is RF sputter deposited and the second material is sputterdeposited.
 3. The method of claim 2 wherein the refractory material iscorundum.
 4. The method of claim 2 wherein the refractory material isselected from the group consisting of glass, corundum, quartz, alumina,beryllia, silicon carbide, boron nitride, and tungsten carbide.
 5. Themethod of claim 4 wherein the refractory material comprises alloys andmixtures of materials selected from the group.
 6. The method of claim 2wherein the refractory material is synthetic sapphire.
 7. The method ofclaim 1 wherein the total thickness of the deposited refractory materialand the second material is limited to that necessary to maintain adesired degree of edge sharpness.
 8. The method of claim 7 wherein thetotal thickness is approximately 500 Angstrom units.
 9. The method ofclaim 7 wherein the thickness of the refractory material isapproximately 300 Angstrom units and the thickness of the secondmaterial is approximately 25 Angstrom units.
 10. The method of claim 2wherein the RF sputter depositing comprises the steps of: disposing theblade in an evacuated chamber having an electrode on which is mounted atarget of refractory material; introducing into the chamber an ionizablegas and establishing a plasma by imposing an RF potential between theelectrode and the blade; depositing on the edge particles dislodged fromthe target by impingement of gas ions formed in the plasma uponcollision of RF excited electrons and the ionizable gas molecules. 11.The method of claim 10 wherein the chamber is evacuated to approximately10 6 Torr and the ionizable gas is introduced to a pressure ofapproximately between 5 and 8 (10) 3 Torr.
 12. The method of claim 11wherein the refractory material is synthetic sapphire, the ionizable gasis Argon and the blade is positioned approximately 2 inches from thetarget, the edge apex being diSposed substantially in a plane parallelto the target and the refractory material is deposited at a rate ofapproximately 30 Angstroms per minute for a period between approximately5 and 10 minutes.
 13. The method of claim 12 wherein the frequency is13.56 MC and wherein the blade is sputter etched prior to deposition ofthe refractory material and a shutter is interposed between the targetand the blade during the step of sputter etching.
 14. The method ofclaim 13 wherein capacitor means is serially connected between the bladeand the RF potential and the shutter is connected to ground duringsputter etching and wherein when the shutter is removed, the RFpotential is connected to the electrode and the blade is connected toground for sputter deposition.
 15. The method of claim 14 wherein thetarget is pre-cleaned prior to sputter etching and wherein duringpre-cleaning the shutter is interposed, the RF potential connected tothe electrode and the shutter is connected to ground.
 16. The method ofclaim 15 wherein the following parameters are maintained duringpre-cleaning, sputter etching and sputter deposition, respectively: 17.The method of claim 10 wherein the second material is RF sputtered inaccordance with the steps of claim
 10. 18. The method of claim 17wherein the second material is deposited to a thickness sufficient toprovide adhesion of the subsequent lubricious material.
 19. The methodof claim 18 wherein the second material is deposited to a thickness ofapproximately 25 Angstrom units and the second material is a metalcontaining material.
 20. The method of claim 19 wherein the secondmaterial is selected from the group consisting of chromium, platinum,aluminum, titanium and iron.
 21. The method of claim 19 wherein thesecond material comprises mixtures and alloys of metals selected fromthe group consisting of chromium, platinum, aluminum, titanium and iron.22. The method of claim 19 wherein the second material is chromium. 23.The method of claim 19 wherein the lubricious material is a polymermaterial.
 24. The method of claim 23 wherein the polymer is selectedfrom the group consisting of polytetrafluoroethylene, polypropylene,polyhexafluoropropylene, polychlorotrifluoroethylene and polyethylene.25. The method of claim 23 wherein the lubricious material comprisescopolymers and telomers of polymers selected from the group consistingof polytetrafluoroethylene, polypropylene, polyhexafluoropropylene,polychlorotrifluoroethylene and polyethylene.
 26. The method of claim 23wherein the polymer is polytetrafluoroethylene.
 27. The method of claim6 wherein the lubricious material is sputter deposited onto the edge.28. The method of claim 27 wherein the lubricious material is depositedto a thickness of at least 1,000 Angstrom units.
 29. The method of claim17 wherein the edge is sputter etched in a first vacuum chamber, theblade is moved through a vacuum interlock to a second vacuum chamber inwhich the edge is sputter deposited with the refractory material, theblade is then moved through a second vacuum interlock to a third vacuumchamber in which the edge is sputter deposited with the second material,and finally the blade is moved through a third vacuum interlock to afourth vacuum chamber which is then vented to the atmosphere to permitblade removal for subsequent coating with the lubricious material. 30.The method of claim 29 wherein blades are continuously sequentiallypasses through the chambers.
 31. The method of claim 1 wherein therefractory material comprises an aluminum oxide compound formed on theelongate edge when material sputtered from an aluminum target combineswith oxygen present in The environment.
 32. The method of claim 10wherein the sputtering rate is increased by the presence of a reactivegas.
 33. A cutting instrument comprising: an elongate edge of narrowincluded angle formed by two intersecting surfaces of a refractorymaterial, an overlay coating of material over the edge for providingadhesion to the refractory material and a lubricious material, and afinal coating of the lubricious material.
 34. The cutting instrument ofclaim 33 wherein the refractory material and the coating are sputterdeposited on the edge.
 35. The cutting instrument of claim 33 whereinthe refractory material is synthetic sapphire.
 36. The cuttinginstrument of claim 34 wherein the refractory material is selected fromthe group consisting of corundum, alumina, glass, quartz, beryllia,silicon carbide, tungsten carbide and boron nitride.
 37. The cuttinginstrument of claim 35 wherein the refractory material is RF sputterdeposited on the edge.
 38. The cutting instrument of claim 37 whereinthe overlay coating is RF sputter deposited.
 39. The cutting instrumentof claim 38 wherein the lubricious material is RF sputter deposited. 40.The cutting instrument of claim 37 wherein the total thickness of therefractory material and the overlay coating does not exceedapproximately 500 Angstrom units.
 41. The cutting instrument of claim 40wherein the thickness of the refractory material is approximately 300Angstrom units and the thickness of the overlay coating is approximately25 Angstrom units.
 42. The cutting instrument of claim 41 wherein theintersecting surfaces are honed surfaces and the narrow included angleis less than approximately 30*.
 43. The cutting instrument of claim 42wherein the narrow included angle is approximately 20*.
 44. The cuttinginstrument of claim 43 wherein the cutting instrument material isstainless steel.
 45. The cutting instrument of claim 43 wherein thecutting instrument material is selected from the group consisting ofstainless steel, carbon steel, chromium steel, tungsten steel,molybdenum steel, and chrome-nickel steel.
 46. The cutting instrument ofclaim 43 wherein the cutting instrument material is an alloy containingmaterial selected from the group consisting of stainless steel, carbonsteel, chromium steel, tungsten steel, molybdenum steel, andchrome-nickel steel.
 47. A method for applying a lubricious material toa cutting instrument having an edge formed by two intersecting surfacesof a refractory material having limited adhesion to the lubriciousmaterial comprising the steps of: sputter depositing on the edge anoverlay coating displaying adhesion to the lubricious material; and thencoating the edge with the lubricious material.
 48. The method of claim47 wherein both the refractory material and the overlay coating materialare sputtered on the edge and the refractory material is syntheticsapphire.
 49. The method of claim 48 wherein both the refractorymaterial and the overlay material are RF sputtered on the edge.
 50. Themethod of claim 49 wherein the refractory material is selected from thegroup consisting of glass, quartz, corundum, alumina, beryllia, siliconcarbide, tungsten carbide and boron nitride.
 51. The method of claim 49wherein the refractory material is an aluminum oxide compound formed bysputter depositing aluminum in an oxygen atmosphere.
 52. The method ofclaim 49 wherein the lubricious material is selected from the groupconsisting of polytetrafluoroethylene, polypropylene,polyhexafluoropropylene, polychlorotrifluoroethylene and polyethylene.53. The method of claim 52 wherein the lubricious material is sputterdeposited on the overlay coating.
 54. The method of claim 49 wherein theoverlay coating is a metal containing material.
 55. The method of claim54 wherein the metal is selected from the group consisting of chromium,platinum, titanium, aluminum anD iron.
 56. The method of claim 54wherein the overlay coating is an alloy containing metal selected fromthe group consisting of chromium, platinum, titanium, aluminum and iron.57. The method of claim 54 wherein the overlay coating material ischromium.
 58. The method of claim 54 wherein the overlay coatingthickness is approximately 25 Angstrom units and the total thickness ofboth the refractory material and the overlay coating is limited to thatnecessary to maintain a desired degree of edge sharpness.
 59. The methodof claim 58 wherein the refractory material coating is approximately 300Angstrom units in thickness.
 60. The method of claim 32 wherein saidreactive gas is oxygen.
 61. The cutting instrument of claim 33 whereinthe cutting instrument is a razor blade.
 62. The cutting instrument ofclaim 35 wherein the cutting instrument is a razor blade.
 63. Thecutting instrument of claim 36 wherein the cutting instrument is a razorblade.
 64. The cutting instrument of claim 37 wherein the cuttinginstrument is a razor blade.
 65. The cutting instrument of claim 38wherein the cutting instrument is a razor blade.
 66. The cuttinginstrument of claim 40 wherein the cutting instrument is a razor blade.